Method of making electrical coils.



C. R. UNDERHILL. METHOD 0F MAKING ELECTRICAL GOILS. APPLICATION FILED JAN.19, 1912.

1,036,937, Patented Aug.2'7,1912.

llllmfliiuf IIJ 1111115511145 UNITED STATES PATENT OFFTCE.

CHARLES E. UNDER'HILL, GF NEW HAVEN, CONNECTICUT, ASSIGNOR TO THE ACME WIRE CQ., OF NEXV HAVEN, CONNECTICUT, A CORPORATION.

METHO t??? MAKING ELECTRICAL COILS.

Specification of Letters Patent.

Patented Aug. 27, 1912.

Application filed January 19,. 1912. Serial No. 672.137.

fo all wiom z5 may concern.'

Ee it known that i, CHARLES R. UNDnR- HILL, a citizen of the United States, res1ding at New Haven, in the county of New iiaven and State of Connecticut, have inlvented a new and useful improvement in the layer-insulation wound spirally svith a progressive overlap butv without. the endclosures. lig. 3 a corresponding view of another form of coil produced hy a moditication oi' my improved method, the thin narrow tapes being in this case wound edge to edge rather than overlapped, and the coil being :furnished at its ends with solid laminated end-closures progressively built up with the building up oie. the layers. Fig. i

a corresponding view of still another coil produced by another modification of my improved method by which the layer-insulation is dillerentiated in bulk by changes in the winding pitch oi the tapes during the.

winding process so that the thickness of each layer is increased on opposite sides of the center of the coil.

My invention relates to an improved method of making electrical coils of that class which consist of alternate layers ot wire and paper or other insulating material. These coils have heretofore been made singly and in multiple. ln making` them singly, wire and a sheet of paper somewhat wider than the length of the llayers of wire are generally wound into a bobbin provided at its respective ends with flanges or heads which serve as guides for the paper. in making -the coils in multi le, a number of windings of wire are spacer upon a spindie or mandrel and paper is inserted between the layers of wine in the form of a sheet sufiiciently wide to be common to all of the windings. Then after the paper and wire have been Wound to the required thick.-

ness, the coils are separated from each other by severing the paper between the windings of Wire. In feeding the paper for 'the pro-` duction of these coils, either singly or in multiple, the sheets invariably exhibit' a tendency to feed out of line, either to the right or left. This tendency is so marked that practically the sheets never feed straight. In malL'ng single coils this tendency must constantly be checked and corrected by guiding the paper by hand which makes the production of the coils singly, difficult and expensive. On the other hand, in practising the multiple method, suiiicient margin is left at the outer ends of the outer windings to provide for enough trimming of the paper to cut away its untrue edges which are thrown away as Waste.

The object of my present invention is to take achantage of the natural tendency oit' paper vfhen fed either by hand or automatically, 'to travel spirally, and by taking advantage of this tendency, to produce coils of superior compact-ness and mechanical and electrical durability, as Well as to produce coils lin which the layer-insulation may be dili'erentiated in bulk so as to be localized with respect to the localization of electrical stress and to provide them with solid`lan1iuated end-closures built. up from the same tapes employed in the production of the layer-insulation.

YWit-h these ends in View, my invention consists in a method of producing,- an electrical'coil consisting in building,` itup from alternate layers of wire and spirally wound thin, narrow tapes of insulating material.

My invention further consists in a method of making an electrical coil consisting in Winding, one upon the other, alternate layers of Wire, and thin, narrow tapes ol' insulating material which are spirally Wound and terminate at their ends in self-wound solid, laminated end-closures.

My invention further consists in a method of making an electrical coil consisting in winding, one upon theother, alternate layers of wire and thin, narrow spirally wound tapes of insulating material which tapes are progressively overlapped soas to ,dilieren-- tinte the layers in bulk in accordance with the electrical stress between thc layers of wire.

- My invent-ion further consists in a method of producing an electrical coil consisting in alternately winding, one upon the other, 4layers of wire and thin, narrow tapes of spirally wound insulating material, the tapes being progressively overlapped and termi nating at their ends in concentrically wound solid end-closures. p

In Fig. l of the drawings I have shown a finished coil in which the outer layer of wire' terial of any suitable character between the layers of wire.

In carrying out my'invention, the thm, narrow tapes of paper or other insulating material, may be. fed and wound in a great variety of ways, dependent upon whether or not the coils are to be produced by hand, or automatically, or semi-automatlcally, and

whether or not they are to be furnished with end-closures, and so on, my invention covering any method of producing electrical' coils in which' layer-insulation issupplied by the insertion between the layers of wire, of spirally wound tapes, whether wound edge to edge or regularly overlapped or progressively overlapped, or in any other way differentiated in bulk.

For the illustration of my invention, I have shown three ways of practising my improved method.

As shown in Fig. 2 of the drawings, the first layer of wire 4 is Wound upon an. ordinary plaper core 5. Beginning at the right, I then feed to the coil a thin, narrow paper tape 6 which is spirally wound upon the layerof wire and progressively overlapped from right to left so that the bulk ofinsulating material is localized at the left end of the coil where the electrical stress between greatest.

the rst and second la ers of wire is the After the winding of the tape has been started from right to left to form the first layer of insulating material, the Winding of the second layer of wire from right to left is begun; but the paper tapes being much widerthan the diameter of the wire will make faster, so to speak, so that the first layer of paper will be wound before the second layer of wire is complete. The wire and tape are wound at different pitches. In this connection Il may state that on account of the economy of time secured the winding of the wire will be begun immediately after the feeding of the paper. After the completion of the rst layer of paper; the tape is severed and fastened upon itself in any suitable manner, as, for instance, by a modicum of some adhesive. No more paper is new fed into the coil until after .the

Iwire.

which the tape is again fed into the coil at the left hand end Atluereofand spirally wound 4with a vprogressive overlap from left to right, whereby the bulkof insulating material is increasedfat the right hand end of the coil where the stress will be t-he greatest 'between the ends of the second and third layers of wire. The winding of the third layer of wire from left to right follows the winding ofthe second layer of paper in the same direction in accordance with the practice above described. When the second layer of paperhas been completed the tape is again severed and fastened and no more tape is fed unt-il after the completion of the third layer of wire, after which the tape is again fed and lwound from right to left, and followed by the winding from right to left of the .flurth Layer of wire. In this way the coil `is`built up until the required size has been reached. When the coil is completedthe end turns of the respective layers vof paper will project beyond the end turns character, with the tape greatly exaggerated in thickness with regard to its width-since it is not practical to represent the paper on the scale of its actual thinness.

The coil illustrated by Fig. 3 of the drawings has its layer-insulation produced by spil-ally winding thin, narrow tapes edge to edge without any overlap, and therefore without any differentiation in bulk. Also, the coil is provided at its respective ends with solid laminated end-closures built up by winding the same tapes turn upon turn or concentrically to the required height. It must be said, however, that the use of such end-closures is in no way limited to coils in which the tapes are wound edge to edge, nor, on'the other hand, are tapes Wound edge to edge in any way limited to use with solid laminated end-closures; the two features are independent of each other though well adapted to be used together.

In producing the specific coil shown by Fig. 3, I begin by winding the. tape 7 turn upon turn upon the paper core 8 until, the right hand end-closure 9 is built up to the height of the top of the second layer of The tape is then severed and fastened. Bginning at the left, at the same time, though not necessarily concurrently, I wind the wire 10 to form the first layer 'of wire. TWhen the wire reaches the inner face o the above described rudimentary right hand end-closure 9 and just before the second layer of -wire is started from right to left, the tape is again inserted and spirally lil 'wound edge to edge from right telefil, proceeding in advance of the second layer of 'wire which is simultaneously wound in the samedirection. The left hand endclosure il is then begun by winding the tape turn fed again and spirally wound-edge to edge in advance of the third layer of Wire from .left to right. Then when the tape completes the second layer of insulation and reaches the rudimentary right hand endclosure it is wound turn upon turn, and the right hand end-closure built up to the height the top of the fourth layer of Wire when the tape isl again severed and fastened. These 4operations are continued in this order until the coil has been built up to the required diameter or until the predeter.

mined mimberl of -turnsor layers of wire and tape have entered into it. ,lf preferred the alternate/layers of Wire and paper may be huilt up together and the end-closures Wound on afterward, or the end-closures xnaylbe applied to the core before the wire and layer insulation is applied, but preferably the end-closures will be built up as the Work of winding the layers of wireand paper progresses.

In the coil illustratedA by Fig. 4 of the drawings, the paper-insulation is different-iated in bulli in accordance with the electrical stress between the layers of Wire, not, in Fig. 2, by a progressive overlapping of the edges of the -tapes, but by doubling up the tapes, so to speak, so as to increase the bulls:- of insulation between the layers of Wire where the electrical stressis localized. This principle may be worked out in different ways. As illustrated in Fig. 4, the Wire 12 is Wound on the paper core k3, beginning from left to right to form the first layer of Wire. At the beginning of the Winding of the second layer of Wire which is Wound from right to left, a tape 14 is inserted and wound spirally from right to left, with a uniform overlap until approximately the middle of the coil is reached, after which its winding pitch is changed so that from about the middle of the coil tothe left hand end thereof, a double thickness of tape is wound on as shown in Fig. 4. When the left hand end of the coil is reached, the tape is severed and fastened upon itself. The second layer of wire progresses from right to left until itreaches the end of its traverse, when the third layer of wire is started from left to right. Now just as the third layer of wire is started winding from left to right, the tape is again fed into the coil, and spirally wound with a uniform overlap until it reaches approximately the middle of the coil after which its Windingpitch is changed so that. it will be Wound of double thickness until it reaches the right hand end of the coil, when the tape will be severed and fastened as before. Meanwhile the third layer of wire follows along from left toA right un- ,til it reaches its limit of traverse, and is reversed to begin the fourth layer of wire, the layers of wire and tape following each other 1n the described alternation until the desired amount of wire and tape have been Wound. As shown in Fie'. Ll, the overlapping of the tape at about the middle of the coil will be made slightly irregular, in shift ing from one winding pitch to another'.

It will be observed that by alternating the doubling. of the tapes on opposite sides of the center of the coil as in Fig.. 4, the localization of the electrical stress between the respective layers of vwire is not only taken care of, but the coil is balanced as to bull; of paper on opposite sides of its center. Ol course', this same principle might be utilized in winding any number of thicknesses; thus the tape might be wound -,for a given distance in two thicknesses, then in three thicknesses, and so on, as far as practical, but in any event the thicknesses would bc balanced on the opposite sides of the center of the coil so as to preserve the symmetry thereof.

It is apparent that the tapes on account of their narrowne'ss and thinness have a greater binding effect both as to the wires and as to each other than can possibly be secured when sheets of paper extending throughout the entire length of the coil are employed. lt is also apparcnt that the endclosures of Fig. 3 may be applied to the coils of Figs. 2l and 4.

I claim A method of 'producing an electrical coil, consisting in alternately winding, one upon the other, layers of wire and thin narrow tapes of insulating material, the tapes being spirally Wound and progressively over lapped, and in winding the tapes concentrically at the ends of the said layers to form solid endfclosures.

In testimony whereof, l have signed this speciication in the presence of two subscribing witnesses.

CHARLES ll.. UNDERHILL.

Witnesses GEORGE l). Surnom; CLARA L. Weno.

Copies et this patent may be obtained for ve cents each, by addressing the lwnfhingtoxi, D. C.

Commissioner o! Patenti. 

